In the past, the scheduling of airplane flights was performed manually. It was assumed that this manual process in scheduling airplane flights optimized the amount of profits to be earned by the airline. If a flight was retimed, then it was assumed that there was a negative impact on the airline's profits. That is, if a flight changed the origin-departure time (i.e., changed the time it left the place of origin and the time it arrived at the place of destination), then it was assumed that there was a negative impact on the airline's profits.
However, there was no consideration of new opportunities that may be gained by retiming flights. For example, if a flight from Dallas to Austin originally left Dallas at 13:00 and was retimed to leave Dallas at 13:20, then there may be new opportunities gained by allowing additional flights to connect in Dallas to fly to Austin. For instance, if a flight from San Diego to Dallas arrived in Dallas at 12:45, then those passengers would not originally be able to make a connecting flight to Austin in Dallas at 13:00. If, however, the flight from Dallas to Austin was retimed to leave Dallas at 13:20, then those passengers on the flight from San Diego to Dallas would now be able to make the connecting flight to Austin in Dallas. Hence, additional revenue may be generated for the airline.
Further, there was no quantification of lost opportunities. For example, if a particular flight was retimed an hour later which caused a passenger to wait an additional hour for that connecting flight, then that passenger may seek out a flight from a different airline as the passenger may be averse to waiting such a long time for the connecting flight. Further, the retiming of a flight may cause a “break” in the connection. “Breaking a connection” may refer to changing the flight time in such a manner as to make that flight no longer connectable for an incoming flight. For example, suppose that the flight from Dallas to Austin originally left Dallas at 13:00 and was retimed to leave Dallas at 12:40. If a flight from San Diego to Dallas arrives in Dallas at 12:30, then those passengers no longer could make the connecting flight to Austin in Dallas at 12:40. Hence, the connection to Austin at Dallas is broken for these passengers.
There have been attempts in quantifying the impact of retiming flights; however, none have been successful, in part due to the non-linearity and discreteness of the solution as well as in part due to the lack of computation efficiency. Each time a flight is retimed, it impacts other flights, such as whether new connections may be made or whether existing connections become broken. Further, passengers' demand for the retimed flight may change. Passengers' demand may refer to the desire a passenger has in taking that flight. Moreover, the schedules of all competing airlines should be considered. Additionally, it may not be feasible for the flight to leave at that time due to slot constraints of the airport. For example, the airport may only have the capacity to allow a limited number of airplanes to leave the airport at around the same time. Hence, there needs to be a consideration of the number of flights to be flown by other airlines. Further, it may not be feasible for the flight to leave at a particular time due to operating constraints of the focus airline. For example, a flight may not be able to be retimed due to gate availability of the focus airline.
If, however, the revenue impact of retiming flights could be quantified taking into consideration the various ramifications as discussed above (e.g., impact on other flights, change in passengers' demand, airport constraints), then airlines could generate a schedule that would maximizing their revenue while taking into consideration the various non-linear ramifications and constraints.
Therefore, there is a need in the art to quantify the revenue and profit impact of retiming flights taking into consideration the various non-linear ramifications and constraints.